One of the features of the English language is a built-in level of redundancy within a certain set of commonly used symbols. While this redundancy provides the writer with choices, it can also make for confusion and, at least among editors, arguments about whether you can use a symbol to express an idea or whether you should write it out using the twenty-six (or 26) letters of the alphabet.

Here are some common examples of our language giving the writer a choice between using a “shorthand” symbol or writing out an idea:

1 = one

15 = fifteen

2,500 = two thousand five hundred

& = and

% = percent

$ = dollar(s)

@ = at the rate of, or at a particular digital address

# = number, as in the quantity of something, or a list number

+ = plus

Numbers have long been a source of contention among editors. In my experience as a ghostwriter of books ranging from novels to self-help books to business books, I’ve found that when the book is “literary,” such as a novel or memoir, the convention is to spell out every number, with some exceptions as noted by the Chicago Manual of Style. These exceptions include street addresses, phone numbers, and the time of day (sometimes). In a novel, for example, you would always write out something like, “The castle was one thousand five hundred years old.” You would never write, “The castle was 1,500 years old.”

At the other end of the spectrum, for non-literary business books, the use of symbols is expected. For example, you would write, “The company shipped 45 units of the product every hour at a price of $56.00 per unit, with a defect rate of less than 1%.” You can violate one of the most ironclad rules of literary writing, which is to never end a sentence with the “%” symbol. You must always write, “…with a defect rate of less than one percent.”

The Challenge of Writing Business Books

In a narrative business book, things can get really confusing! There will be times when a number or symbol will appear in a narrative paragraph, and its use seems odd. For example, “The Ajax Company manufactures a complete line of household goods ranging from dishwashers to can openers. They ship to every continent on the globe, and their customer service center in Boise, Idaho is open 24 hours a day, 7 days a week.”

Because the paragraph is narrative, it seems wrong to use the numbers 24 and 7. It looks like commercial copy, not like a book. You want it to read, “… their customer service center in Boise, Idaho is open twenty-four hours a day, seven days a week.”

But in the next paragraph, you present a lot of data: “In 2018, the Ajax Company achieved an ROI of 8% on sales of $8 million, with an EBITDA of $580,000, putting the company, with its workforce of 1,200 employees, in the top 10% of the white goods market in the four-state region.”

Note that we wrote “four-state region” rather than “4-state region.” This is because the convention is to write out numbers ten and below – except when you’ve got a string of numbers:

“On Tuesday, Ajax shipped 75 washers, 60 dryers, 14 home freezers, and 6 walk-in freezers.” You could write out “six walk-in freezers,” but if a business person is glancing at the row of numbers, it might make more sense to keep them uniform.

Businesspeople also love to use symbols such as # and &. For lists in column form, the pound sign makes sense:

#1

#2

#3

But in a narrative, always write out the word “number.” Such as, “Ajax aims to be number one in its market.”

As for the ampersand, I never use it unless it’s part of a company or law firm name, and it appears on their company documents. Examples include The Procter & Gamble Co. (P&G) and the law firm Kirkland & Ellis.

As a writer, always strive for consistency and clarity, and keep in mind the expectations of your reader!

Thomas Hauck is a professional author, ghostwriter, and book editor serving global clients.